1. Field of the Invention
The present invention, in general relates to drilling machines and, more particularly, to all-terrain self-propelled drilling machines that are maneuverable and operable by remote control.
Drill units are used for a variety of purposes including core drilling, blast hole drilling, and surface grout hole drilling as well as to satisfy other special applications.
Sometimes the work environment presents cramped quarters where tight ninety-degree turns must be accomplished, such as is found in galleries at concrete water dams.
Sometimes steep inclines must be traversed including going up and down stairs or navigating up or down a steep incline for a prolonged period of time. This condition produces a potentially damaging condition to an engine in that the oil supply will congregate on one side of a steeply inclined internal combustion engine, possibly starving the oil sump of a reservoir of lubricating engine oil. Operating an engine at an angle where it is deprived of a continuous flow of lubricating oil can cause severe engine damage to occur, sometimes very quickly.
Similarly, hydraulic oil that is used to operate the hydraulic systems may not be available for use at a normal outlet location of a first side frame member tank if the tank is severely canted. This problem is exacerbated when some of the hydraulic oil is contained in one or more extended (or partially extended) hydraulic cylinders.
Certain operating environments may also present hazardous conditions for operation. Under such operating conditions it is desirable to be able to maneuver and also to operate the drill unit from a remote location. in some environments, toxic or noxious fumes may be present, such as may occur during certain grouting applications and in other situations which present or encounter these and other types of hazardous materials.
An especially acute danger for humans involves environments where higher than normal levels of radiation are present, such as those produced from the decay of radioactive isotopes. It is not safe for an operator to remain for prolonged periods of time in such locations. For some locations the danger may be so severe, because the radiation levels may be so high, that it is not wise to risk exposure for even short periods of time.
An example of such a situation involves the storage of nuclear waste. Nuclear waste is a by-product that arises from the operation of nuclear power plants and especially from nuclear weapons research and production. In particular, the nuclear waste related to nuclear weapons production is especially radioactive and therefore especially hazardous.
There are numerous locations in the United States (and also in other countries located throughout the world) where nuclear waste has been buried in underground storage tanks. In particular some of the nuclear waste from nuclear weapons production has been stored in either poorly designed or marginally designed storage tanks, and sometimes at poorly chosen site locations.
Examples of poor site selection for the storage of highly radioactive nuclear wastes include locations that are prone to geological activity, such as earthquakes, geothermal activity, or ground settling. An especially poor site selection is found where the earthen material that is disposed underneath or around the storage tank is porous. An especially poor site for the storage of nuclear waste is one that is disposed atop or near an aquifer. Perhaps the worst location would involve a storage tank that is disposed on porous soil leading to an aquifer.
During the "cold-war", compelled by the fear of foreign nuclear power superiority, surprisingly little consideration was given to such basic issues as mentioned above. Today, some of these storage tanks are known to be leaking highly radioactive nuclear waste into the soil that is disposed either under or around certain of the storage tanks. The problem thus created is immense.
There is a great danger that such leakage will eventually migrate a sufficient amount so as to reach an aquifer. Depending upon the particular radioactive isotopes that are leaking, contamination of an aquifer can potentially do an enormous amount of damage. This is because the water within the aquifer is moved according to the flow patterns that normally exist within the aquifer itself. These aquifer flow patterns are as capable of transporting pure water as they are of transporting radioactive contaminated water.
If an aquifer which supplies drinking or irrigation water is involved, there is an eminent danger present to all life forms which may either use or come in contact with radioactive contaminated water from the aquifer. Furthermore, the water consumption chain and also the various food chains are also impacted.
Crops and fields can become irradiated by radiation levels in the irrigation water, thereby posing a hazard to all life forms that may either pass by or graze on the crops or in the irradiated fields. The radiation can potentially be absorbed by the bodies of animals that either drink the radioactive water or graze upon the irradiated crops. Later, the contamination can be further spread along the food chain as these animals are themselves consumed by other animals disposed along the food chain, thus spreading the contamination in unpredictable ways.
Contamination can spread in other ways as well. If dairy cattle, for example, consume radioactive material, it can spread through their milk to their nursing young, and possibly even to humans. Accordingly, to stop this from occurring, large tracts of productive farm lands may become unusable for hundreds, or even thousands of years, and perhaps for even that many centuries by the radioactive contamination of even one key aquifer.
The potential human cost in terms of loss of life, physical and emotional suffering, and disease arising from the radioactive contamination of an aquifer is enormous. The environmental impact is nearly unimaginable. The economic costs are so high as to be almost incalculable.
If a polluted aquifer leaches into a river thus irradiating the river, the dangers and potential impacts are multiplied many fold. An entire swath of the river beginning at the point of contamination and extending down-river into the mouth of an ocean may be rendered both hazardous as well as sterile. The river itself can become too hazardous for any type of usage including its being used as a source of drinking water, irrigation water, and for recreational purposes. The magnitude of the disruption of life for countless generations is virtually unimaginable in some of the worst case scenarios that are currently being considered. Civilization, as it currently exists along such river banks, would be dramatically altered, even eliminated, if the river were to become contaminated with a highly radioactive waste.
In terms of environmental impact, perhaps one of the greatest and most imminent risks ever to confront life on this planet, comes from leaking storage tanks that contain radioactive substances. These substances include all manner of substances including solids, liquids, sludge, and even gases. Water that has been used in radioactive situations can itself become radioactive as the particulates within the water are themselves irradiated. Depending upon the particular variables affecting each storage location, the dangers associated with the spread of the nuclear waste material varies greatly.
The economic costs of containment at such installations are staggering and reach into the many billions of dollars. Certain of the proposals for achieving containment of leaking nuclear wastes, are themselves, uncertain as to efficacy. It is possible that billions of dollars can be spent toward such containment measures without achieving a lasting or satisfactory level of success.
One particularly promising approach is a form of surface grouting, a procedure which has a proven record of success in the containment of leaching substances, especially liquids. Grouting has been used to form a barrier to stop leaching as well as to stop leakage's. The size and shape of the barrier formed by surface grouting techniques is varied to establish a contour to match the application at hand.
The procedure is modified for storage tanks by drilling a series of holes around a leaking (or not yet leaking storage tank) so as to form a lattice of bore holes resembling a semi-sphere underneath the targeted storage tank. Then a grout, such as a urethane grout, is injected into the holes, preferably by long hole chemical grouting techniques as are taught by U.S. Pat. No. 5,342,149, to McCabe et al, that issued on Aug. 30, 1994, which is incorporated by reference herein.
Such an approach can be used to create a urethane (or other grout material) containment semi-sphere disposed underneath and around the targeted storage tank. The semi-sphere can be any desired diameter thus extending far enough away from a leaking storage tank so as to encompass any material which may have already leached into the soil under the tank. The barrier thus formed acts as a storage tank by and of itself. Of course, the shape of the urethane containment barrier can be other than a semi-sphere if desired.
A surface grouting approach as a means of containment relies upon proven technology with relatively minor changes and as such is likely to offer success. If desired the same approach can be utilized to create a plurality of urethane (or other grout material) containment hemispheres (or other shape), each one larger than the other and each one concentrically disposed with respect to the other. Such an arrangement can provide additional levels of protection for the most troublesome of locations. This approach offers a margin of safety, a fail-safe approach, toward the containment of radioactive wastes.
Such extremely hazardous working environments demand that the drill unit be both navigable and operable by remote control means. The background radiation levels in such locations may not allow for prolonged human operation of a drill unit near such nuclear waste types of storage tanks. Upon reaching the actual job site, which may be on the surface of the ground in proximity to a storage tank or in an access tunnel within the superstructure surrounding such a storage tank site, it is desirable to be able to remotely align the drill head in the proper position and accomplish as much of the drilling from a remote location as is possible without human assistance at the actual drilling site.
Depending upon the danger it may be possible for a human wearing protective clothing to enter the location for brief periods of time. Clearly a drill unit that can remotely reach a location and perform as much work as possible without an operator having to stand beside the unit is a useful device.
When drilling in radioactive locations, there is another danger that arises due to the hole that is being drilled in that it may open up a direct path to a highly radioactive source. If for example, hundreds of feet of earthen material or concrete or the like was separating an operator from a radioactive source, the mere drilling of a hole to the radioactive source removes that intervening barrier and exposes an operator to substantial risk at the drill site. In addition, any material that is extricated from the bore hole may be highly radioactive and contaminate the area adjacent to the drill site.
This does lend yet another advantage that is available through the use of surface grouting techniques for the containment of leakage's at nuclear waste storage sites. That is that such techniques often extricate core samples during the drilling process. These core samples can be studied for radioactive contamination and are therefore useful in determining the extent that radioactive wastes have leached into the soil. The exact locations of radioactivity can be "mapped " by studying the core samples, thus allowing for precise determination of the size, shape, and location or depth of the barrier that is required for containment.
However, the work environment that is in close proximity to the drill unit can be made especially hazardous during the actual drilling operation at a potentially radioactive site. This may occur without warning as one particular core sample can be especially radioactive once the drill has intersected with leaching radioactive material.
It is not always necessary to operate the drill unit from a great distance away. Lead or other types of shielding may be placed immediately around the drill unit forming a radioactive barricade, behind which, an operator may safely operate the drill unit.
This possibility is mentioned in that the distance separating an operator from a drill unit when it is being either maneuvered or operated in a radioactive environment need not be excessive, but rather merely sufficient to ensure the safety of the operator. Under such conditions, the ability to operate the drill unit from only a short distance away can nevertheless be especially valuable.
This requires that a good deal of information be made available remotely. For example the location of the drill unit must be known at all times as well as the condition of all of its systems. In the event of a malfunction, it must be possible to send in another unit and remotely connect it with a malfunctioning unit in order to retrieve the crippled unit.
Other types of tanks can, similarly, be leaking potentially dangerous substances. For example petroleum, in its many forms, can also do considerable damage to the earthen material that it comes into contact with as it leaks from a storage tank. It can also cause enormous environmental damage by leaching into an aquifer. Although the hazards may be less severe than those present in radioactive environments, it is still advantageous to be able to use surface grout injection technology, as mentioned above, as a method for containing such types of leakage's. It is desirable to be able to perform containment operations from a remote location whenever it is deemed to be either hazardous of when the potential to become hazardous exists at the site itself.
Accordingly there exists today a need for a drill unit that can navigate in cramped quarters, ascend steep inclines, prevent engine damage from a lack of lubricating oil from occurring, and be maneuvered, operated, and monitored remotely.
Clearly, such an apparatus is a useful and desirable device.
2. Description of Prior Art
Drill units are, in general, known. For example, the following patents describe various types of these devices:
U.S. Pat. No. 3,470,968 to Melsheimer et al, that issued on Oct. 7, 1969; PA1 U.S. Pat. No. 3,642,075 to Wills, that issued on Feb. 15, 1972; PA1 U.S. Pat. No. 4,172,615 to Hakes, that issued on Oct. 30, 1979; PA1 U.S. Pat. No. 4,303,130 to Bonca, that issued on Dec. 1, 1981; PA1 U.S. Pat. No. 4,363,519 to Howard, that issued on Dec. 14, 1982; PA1 U.S. Pat. No. 4,501,199 to Mashimo et al, that issued on Feb. 26, 1985; and PA1 U.S. Pat. No. 4,508,035 to Mashimo et al, that issued on Apr. 2, 1985.
While the structural arrangements of the above described devices, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices.